Hibernate Native Scalar Query
In this section, you will learn Hibernate Native Scalar Query .
Using HQL or criteria query in Hibernate, you can execute nearly any type of SQL query. Even so some developer complaint about slowness of statement generated by Hibernate and they opt to generate their own SQL statement. These developer generated query is known as Hibernate Native SQL Query.
Hibernate Native Scalar Query is the most basic SQL query. In this query, we fetch list of scalars or values from one or more database tables.
EXAMPLE
In the below example, we are fetching three scalars (values) from worker table which are firstname, birth_date, cell_phone. For handling query results, we are using setResultTransformer( Criteria.ALIAS_TO_ENTITY_MAP ) method which converts each row of result into a Map.
The project hierarchy is given below :
The query for creating table worker is given below :
CREATE TABLE `worker` ( `worker_id` bigint(10) NOT NULL auto_increment, `firstname` varchar(50) default NULL, `lastname` varchar(50) default NULL, `birth_date` date NOT NULL, `cell_phone` varchar(15) NOT NULL, PRIMARY KEY (`worker_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1
CODE
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- Database connection settings --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://192.168.10.13:3306/anky</property> <property name="connection.username">root</property> <property name="connection.password">root</property> <property name="connection.pool_size">1</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <property name="current_session_context_class">thread</property> <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <property name="show_sql">true</property> <property name="hbm2ddl.auto">validate</property> <mapping class="net.roseindia.Worker"/> </session-factory> </hibernate-configuration>
Worker.java
package net.roseindia;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "worker")
public class Worker {
@Id
@GeneratedValue
@Column(name = "worker_id")
private Long workerId;
@Column(name = "firstname")
private String firstname;
@Column(name = "lastname")
private String lastname;
@Column(name = "birth_date")
private Date birthDate;
@Column(name = "cell_phone")
private String cellphone;
public Worker() {
}
public Worker(String firstname, String lastname, Date birthdate,
String phone) {
this.firstname = firstname;
this.lastname = lastname;
this.birthDate = birthdate;
this.cellphone = phone;
}
public Long getWorkerId() {
return workerId;
}
public void setWorkerId(Long workerId) {
this.workerId = workerId;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getLastname() {
return lastname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
public Date getBirthDate() {
return birthDate;
}
public void setBirthDate(Date birthDate) {
this.birthDate = birthDate;
}
public String getCellphone() {
return cellphone;
}
public void setCellphone(String cellphone) {
this.cellphone = cellphone;
}
}
HibernateNativeScalarQuery.java
package net.roseindia;
import java.util.List;
import java.util.Map;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
public class HibernateNativeScalarQuery {
private static SessionFactory sf;
private static ServiceRegistry serviceRegistry;
public static void main(String[] args) {
try {
Configuration configuration = new Configuration();
configuration.configure()
.setProperty("hibernate.show_sql", "false");
;
serviceRegistry = new ServiceRegistryBuilder().applySettings(
configuration.getProperties()).buildServiceRegistry();
sf = configuration.buildSessionFactory(serviceRegistry);
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
System.out.println("***Hibernate Native Scalar Query Example***");
System.out.println("-------------------------------------------");
Session session = sf.openSession();
try {
session.beginTransaction();
String sql = "SELECT firstname, birth_date,cell_phone FROM worker";
Query query = session.createSQLQuery(sql);
query.setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP);
List data = query.list();
for (Object object : data) {
Map row = (Map) object;
System.out.println("First Name: " + row.get("firstname"));
System.out.println("Birth Date: " + row.get("birth_date"));
System.out.println("Cell Phone: " + row.get("cell_phone"));
System.out
.println("-------------------------------------------");
}
session.getTransaction().commit();
} catch (HibernateException e) {
if (session.getTransaction() != null)
session.getTransaction().rollback();
e.printStackTrace();
} finally {
session.close();
}
}
}
OUTPUT
After execution, you will get the following results on console:
***Hibernate Native Scalar Query Example*** ------------------------------------------- First Name: Sushmita Birth Date: 1987-05-21 Cell Phone: 919595959595 ------------------------------------------- First Name: Nayana Birth Date: 1987-06-30 Cell Phone: 919191919191 ------------------------------------------- First Name: Sameer Birth Date: 1981-09-30 Cell Phone: 919191929292 -------------------------------------------